• Journal of the Korean Society of Combustion
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• v.3 no.1
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• pp.1-10
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• 1998

Lots of techniques are adopted for a flame stabilization and a high-load combustion. But the techniques being used were passive control method which have to change combustor shape like pilot flame, flame stabilizer, pressure profile, etc. Active control method which is not necessary to transform its shape is employed. Acoustical excitation is broadly used for its convenience in changing frequency and intensity. Both acoustical excitation and flame stabilizers were adopted to study their relationship. So, we investigated flammability limits. Flame visualization. And mean temperature in the condition of various frequencies, intensities, and flame stabilizers. As a consequence, flammability limit were advanced in acoustically excited flame at some frequencies. Coherent structure was extended to the downstream region through acoustical excitation and a size of vortice was curtailed. Also width of recirculation zone was magnified. In addition, Effects of acoustical excitation was stood out at 25mm flame stabilizer rather than another ones.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.111-112
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• 2020

In the case of, the ignition of flammable external materials by the radiant flame and the accompanying fire in the upper layer are occurring every year, and in the case of the Flashover prediction formula, the limit is reached through the surface area of the space and the factor. Predicts heat release rate. In this study, the critical heat release rate of each prediction formula was calculated based on the ISO 9705 model.

• Fire Science and Engineering
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• v.18 no.3
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• pp.57-73
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• 2004

Quantitative safety analysis through a fault tree method has been conducted for a fire broken out over the spilling LNG from a pilot LNG tank, which may have 4 types of scenarios causing potentially risky results. When we consider LNG release from venting pipelines as a first event, any specific radius of Low Flammable Limit(LFL) has not been built up. The second case of LNG outflow from the rupture of storage tank which will be the severest has been analyzed and the results revealed various diffusion areas to the leaking times even with the same amount of LNG release. As a third case LNG leakage from the inlet/outlet pipelines was taken into consider. The results showed no significant differences of LFL radii between the two spilling times of 10 and 60 minutes. Hence, we have known the most affecting factor on the third scenario is an initial amount of LNG release. Finally, the extent of LFL was calculated when LNG pipelines around the dike area were damaged. In addition, consequence analysis has been also performed to acquire the heat radiation and flame magnitude for each case.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.4
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• pp.40-49
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• 2016

This study aims to confirm the characteristics of low swirl combustion at our low swirl model combustor. To do it, it is experimentally conducted by evaluating the flame shape, stability region and emissions according to the swirl angle. The most significant feature of low swirl combustion is a occurrence of lifted flame. Such lifted flames happen to combine exquisitely propagating feature of premixed flame with diverging flow. This feature of lifted flame was confirmed through a velocity flow field and visualized the flame in this model combustor. The visualized flame was classified according to the thermal power and equivalence ratio. The variation study in swirl angles showed that the lean flammable limit could be extended only by swirl angles. Also, as the swirl angle increased, it was confirmed that the NOx and CO emissions were decreased due to the mixing enhancement and shorter resident time.

• Journal of the Korean Society of Combustion
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• v.20 no.1
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• pp.32-42
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• 2015

The combustion instability was experimentally investigated in model gas turbine combustor with dual swirl burner. When such instability occurs, a strong coupling between pressure oscillation and unsteady heat release excites a self-sustained acoustic wave which results in a loud sound, and can even cause fatal damage to the combustor and entire system. In present study, to understand the combustion instability with a premixed mixture, the detailed periods of pressure and heat release data in unstable flame mode were investigated by various measurement methods at relatively rich condition and lean condition near flammable limits. Also, to prepare the utilization of synthetic natural gas (SNG) fuel in gas turbine system, an investigation was conducted using a simulated SNG including methane as a reference fuel to examine the effects of $H_2$ content on flame stability. These results provide that the instability due to flash-back behaviour like CIVB phenomenon occurred at rich condition, while the repetition of relighting and extinction caused the oscillation of lean condition near flammable limit. From the analysis of $H_2$ content effects, it is also confirmed that the instability frequency is proportional to the laminar burning velocity at both rich and lean condition.

• Fire Science and Engineering
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• v.25 no.2
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• pp.114-119
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• 2011

Explosion limit and flash point are the major combustion properties used to determine the fire and explosion hazards of the flammable substances. In this study, in order to predict upper explosion limits (UEL) for acids and ketones, the upper flash point of these were measured under the VLE (vaporliquid equilibrium) state by using Setaflash closed cup tester (ASTM D3278). The UELs calculated by Antoine equation by using the experimental upper flash point are usually lower than the several reported UELs. From the given results, using the proposed experimental and predicted method, it is possible to research the upper explosion limits of the other flammable substances.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.182-193
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• 2022

Purpose: By measuring and evaluating the risk of biodiesel through non-volatile residue (NVR) and flash point and explosion limit measurement at a specific temperature according to ASTM test standards, the risk of chemical fire causative substances is identified and a universal evaluation method By derivation and securing the risk-related data of the material, it can be used for the identification and analysis of the cause of the fire, and it can be applied to the risk assessment of other chemical substances Method: In order to measure the risk of biodiesel, it was measured using the non-volatile residue(NVR) measurement method, which measures how much flammable liquid is generated at a specific temperature. Heating was tested by applying KS M 5000: 2009 Test Method 4111. In addition, the flash point was measured using the method specified in ASTM E659-782005, and the energy supply method was measured using the constant temperature method. In addition, the explosion limit measurement was conducted in accordance with ASTM E 681-04 「Standard test method for concentration limits of flammability of chemicals(Vapors and gases)」 test standard. Result: As a result of checking the amount of combustible liquid by the non-volatile residue (NVR)measurement method, the non-volatile residue(NVR) of general diesel when left at 105±2℃ for 3 hours was about 30% (70% of volatile matter) and about 4% of biodiesel. In addition, similar results were obtained for the non-volatile residue(NVR)heating temperature of 150±2℃, 3 hours and 200±2℃ for 1 hour, and white smoke was generated at 200℃ or higher. In addition, similar values were obtained as a result of experimentally checking the explosion (combustion) limits of general diesel, general diesel containing 20% biodiesel, and 100% biodiesel. Therefore, it was confirmed that the flammability risk did not significantly affect the explosion risk. Conclusion: The results of this study suggested the risk judgment criteria for mixtures through experimental research on flammable mixtures for the purpose of securing the effectiveness, reliability, and reproducibility of the details of the criteria for determining dangerous substances in the existing Dangerous Materials Safety Management Act. It will be possible to provide reference data for the judgment criteria for flammable liquids that are regulated in the field. In addition, if the know-how for each test method is accumulated through this study, it is expected that it will be used as basic data in the research on risk assessment of dangerous substances and as a basis for research on the determination of dangerous substances.

• Korean Chemical Engineering Research
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• v.55 no.5
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• pp.618-622
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• 2017

Gasoline is a widely used product as a source for energy in homes, the automotive industry, and for industrial power generation, and it is also a product with a high risk of fire and explosion. In this study, to examine the risk for explosion for gasoline, PG, MG and RG, which are categorized according to octane number, were used as test specimens to measure their explosion limit according changes in oxygen concentration. The explosion limit for 21% oxygen concentration in air were confirmed to be 1.5~10.9%, 1.4~8.1%, and 1.3~7.6%, respectively, and the MOC for each of the test sample were confirmed to be 10.9%. The explosion limit measured in the test performed in this study confirmed between a 1.2%~7.6% wider explosion limit for the currently accepted MSDS for gasoline, and therefore it is considered that the results of this study can provide significant reference for preventing fires and explosions for process used gasoline.

• Fire Science and Engineering
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• v.31 no.3
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• pp.1-10
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• 2017

This study examined the risk of accidents when handling hazardous materials in hazardous materials storage facilities without safety facilities. In the case of illegal dangerous cargo containers, the burning rate is very fast in the case of fire, which leads to explosions, that are damaging and difficult to control. In addition, accidents that occur in flammable liquid hazardous materials are caused mostly by accidents that occur in the space due to leakage. Therefore, the variables that affect these accidents were derived and the influence of these variables was investigated. Numerical and computational fluid dynamics programs were used to obtain the following final results. First, when a flammable liquid leaks into a specific space, it is influenced by temperature and relative humidity until a certain concentration (lower limit of combustion) is reached. In the case of temperature, it was found that the reaching time was shorter than the flash point In addition, the effect of variables on pool fire accidents of leakage tanks is somewhat different, but the variables that have the largest influence are the wind speed. Therefore, it is expected that the results of this study will be used as basic data for similar numerical analysis and it will provide useful numerical information about the accidental leakage of hazardous materials under various research conditions.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.25-31
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• 2017

The flash point, explosion limits, autoignition temperature(AIT) are important combustible properties which need special concern in the chemical safety process that handle hazardous substances. For the evaluation of the flammable properties of n-butylacetate, this study was investigated the explosion limits of n-butylacetate in the reference data. The flash points, fire points and AIT by the ignition delay time of n-butylacetate were experimented. The lower flash points of n-butylacetate by using the Setaflash and Pensky-Martens closed-cup testers were $24^{\circ}C$ and $26^{\circ}C$, respectively. The flash points of n-butylacetate using the Tag and Cleveland open cup testers are measured $31^{\circ}C$ and $40^{\circ}C$, respectively. And the fire points of n-butylacetate by the Tag and Cleveland open cup testers were measured $32^{\circ}C$ and $41^{\circ}C$. The AIT of n-butylacetate measured by the ASTM 659E tester was measured as $411^{\circ}C$. The lower explosion limit of lower flash point $24^{\circ}C$, which was measured by the Setaflash tester, was calculated to be 1.40 vol%. Also, the upper explosion limit of upper flash point $67^{\circ}C$ the Setaflash tester was calculated to be 12.5 vol%.